Title: THE EFFECTS OF ENVIRONMENTAL AND MECHANICAL VARIABLES ON CORROSION FATIGUE CRACK PROPAGATION RATE IN A HIGH STRENGTH STEEL——Quantitative Understanding of the Corrosion Fatigue Crack Growth Rate in a High Strength Steel
Abstract:The behaviour of corrosion fatigue crack propagation in 4330M steel in distilled water has been investigated. The rate of stress corrosion crack propagation in distlled water, the fatigue crack propag...The behaviour of corrosion fatigue crack propagation in 4330M steel in distilled water has been investigated. The rate of stress corrosion crack propagation in distlled water, the fatigue crack propagation in argon and the corrosion fatigue crack propagation in distilled water with stress ratio R=0.2, 0.6, 0.7 and 0.8 were measured. The rate of stress corrosion crack growth per second da/dt and the rate of fatigue crack growth per cycle da/dN are related to the crack tip stress intensity factor K and cycle range of stress intensity ΔK respectively.A BASIC computer program has been developed to calculate the cyclic rate of stress corrosion crack propagation (da/dN)_(SCC) with the experimental data of the time rate da/dt. The cyclic rate of corrosion fatigue crack propagation (da/dN)_(CF) based on both the linear summation model and the competition model were also calculated by computer respectively and compared with the experimental data. It is shown that the experimental results consist the competition model suggested by I. M. Austen. However, a modification to the competition model was represented in which an interaction term is added.The basis of this modified competition model is that: the fatigue and the stress corrosion crack growth process including their interaction terms are mutually competitive and that the crack will propagate at the fastest. Thus, the cyclic rate of stress corrosion fatigue crack growth (da/dN)_(CF) is (da/dN)_(CF)=(da/dN)_F+(da/dN)_(int F) or (da/dN)_(CF)= (da/dN)_(SCC)+ (da/dN)_(int S) where (da/dN)_F and (da/dN)_(SCC) are the cyclic rate of fatigue crack growth and of stress corrosion crack growth respectively, and (da/dN)_(int F) and (da/dN)_(int S) are the additional value of da/dN due to the interaction between the environment (water) and fatigue on (da/dN)_F and (da/dN)_(SCC) respectively.Some discrepancies of experimental results in quantitative understanding of corrosion crack growth rate were explained and treated uniquely this model.The results presented here shows that the steel used in this paper is appropriate for systematic study of mechanisms of stress corrosion fatigue crack propagation.Read More
Publication Year: 1983
Publication Date: 1983-03-18
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot